Brush for dynamo-electric machines.



E. T. MUG. BRUSH FOR DYNAMO'ELEGTRIU MAOHI APPLICATION FILEDSEPT.19,1904.

Patented Sept. 13, 1910 7108.72 for:

Fezzo and A it own perienced in e EDWARD r. MUG,

OF NORWOOD, OHIO, ASSIGNOB, TO THE BULLOCK ELECTRIC MANU- FACTURINGOOMPA NY, A CORPORATION OF OHIO.

BRUSH FOR DYNAMO-ELECTRIC MACHINES.

Specificationof Letters Patent. Patent ds h 13 1910 Application filedSeptember 19, 1904. Serial No. 225,064.

To all whom 'it'may concern:

Be it known that I, EDWARD T. MUG, citizen of the United States,residing at Nor- Wood, in the county of Hamilton and State of Ohio, haveinvented certain new and useful Improvements in Brushes for Dynamo-Electric Machines, of which the "following is a full, clear, and exactspecification.

.My present invention relates to brushes for dynamo-electric machinesand to the method of connecting conductors made of flexible material tocarbon brushes.

Heretofore reat difficulty has been execting a good electrical andmechanical connection between the highresistance carbon 'brushordinarily employed in dynamo-electric machines and the low resistancebraided flexible conductor or pig tail connected thereto.

The flexible con-- ductor has been connected to the carbon brush in agreat many ways, for instance, by

soldering it directly to the copper plated surface of the brush, bysoldering it. in a slot formed in the brush, by fastening it to abolt'placed in a transverse hole drilled through said brush, by clamping andsolderlng it to a metall c clip, which is then in turn soldered to thecopper plating of the brush, etc. soldered connections areobjection'able on account of the gliability of the solder melting andthe connection between the conductor and brush becoming loosened,

if not entirely separated, if the brush should become overheated Whencarrying an ex- CBSSIVB. amount of current. The other methods aboveenumerated are objectionable in that they require a multiplicity ofparts which are expensive to construct and as semble. V

The object of my invention is to improve the method of attaching to thecarbon .brush the flexible braided Wire conductor or cable commonly,employed to carry the current transmitted to or from said brush, so asto enable said brush to carry without undue heating the full currenttransmitted thereto or therefrom.

The invention aims to reduce the cost of the brush and attached pigtail, and to produce a reliable article of manufacture which will not besubjected to the objections which-have been raised against the olderforms of. brushes. To this end I form the brush so that one end of theflexible conductor, or pig tail is embedded in the body of the brush andis preferably flared out so as to bring the individual wires composingthe conductor into intimate contact with the material of which thecarbon brush is made. The method of connecting the flexible conductor tothe brush which 1 prefer to employ is to embed one end of said conductorin the material of which the brush is made when said material is in aplastic. semi-plastic, or pulverulent conditiom and thenmold the brushinto the desired shape.

In the accompanying drawing, which illustrates the preferred embodimentof my invention, Figure 1 is a perspective view of a'carbon brush withthe flexible pig tail attached thereto in accordance with my invention,the said "pigtail entering the brush through an opening in its upperend; Fig. 2 is a vertical sectional view of the brush shown in Fig. 1;Fig. 3 is a section on the line 3 B of Fig. 2; and Fig. 4 is aperspective view of a modified form of my invention illustrating theflexible lead or.

pig tail entering the carbon brush through an opening in its side.

Referring now to Figs. 1, 9, and 3, A represents the block of carbonforming the brush proper. Embedded in the material of which said carbonblock is made,pret'erably when said material is in a plastic,semiplastic, or pulverulent condition in a mold is the flared end of aflexible braided wire conductor or pig tail B, the separate strands ofsaid flared end being indicated in dotted lines Fig. 2 at C. A bundle ofunbraided wires may be used if so desired. It will be noted by referenceto Figs. 1 and 2 that the end of the flexible conductor B which isembedded in the carbon block enters said block an appreciable distancebefore it is unraveled or flared out. This is indicated clearly at D. Asshown in Fig. 3

the strands of the flared end of the flexible in the side of the brush,as it often happens that such a brush is employed in a brush holder,which has a spring finger bearing on the top surface of the brush, andby bringing the flexible connection out through the side of the brushall interference with such finger is obviated. The flexible leadB ispreferably provided with a terminal clip at its opposite end, said clipbeing indicated in Fig. 1 by F.

Such a brush as just described may be employed to carry much heaviercurrents than the ordinary carbon brush with the pig tail soldered, orotherwise fastened thereto, and it will be readily seen that a very intimate connection, electrically and mechanically speaking, is madebetween the parts of the carbon brush and the flexible c011- ductor.

It is seen that in a brush constructed according to my invention no holeor channel need be drilled into or through the brush for the receptionof holding screws or solder. In fact, the four sides of the brush areentirely uninterrupted or unbroken except in the modification shown inFig. 4, in which the flexible conductor emerges from the brush at theside near the top.

Although I have illustrated the preferred embodiment of my invention, Ido not care to be limited thereto, as various changes may be madewithout departing from the spirit. and scope of my inyention, and I aimin the appended claims to cover all such changes.

Having thus described my invention, what I claim as new and desire tocover by Letters Patent is r 1. A carbon brush, and a flexible conductorcomposed of a plurality of strands having the strands at one endseparated one from another and embedded in said brush.

2. A carbon brush, and a flexible conductor composed of a plurality ofwires, one

BGEJQB end of said conductor being flared and embedded in said brush.

3. A carbon brush, and a flexible braided wire conductor having one endunraveled and embedded in said-brush."

4;. A carbon brush, and a flexible braided wire conductor having one endunraveled and embedded in said brush said conductor entering saidbrushan appreciable distance in its braided condition.

. 5. A carbon brush, and a flexible conductor composed of a plurality ofwires in a compact bundle, one end of said conductor being spread outthrough the body of said carbon brush.

6. A carbon brush, and a flexible conductor composed of a plurality ofwires in a compact bundle, one end of said conductor being spread outthrough the body of said carbon brush, said conductor entering saidcarbon brushan appreciable distance in its compact form.

-7. The method of connecting a flexible conductor with a carbon brushwhich consists in embedding the flared or unraveled end of saidconductor in the material of which the brush is made when said materialis in a plastic, semi-plastic or pulverulent condition, and then moldingthe brush into the desired shape.

8. A carbon brush, a flexible conductor composed of a plurality of wiresin a compact bundle, one end of said conductor being spread out throughthe body of said brush,

'saidbrush having unbroken or uninter- In .testimony whereof I a-flix mysignature,

in the presence of two witnesses. v

. EDWARD T. MUG. Witnesses:

B. A. BEHREND, FRED J. KINSEY.

